title: Flow microfluorometric analysis of H-2L expression.
abstract: The cell surface expression of H-2L, a major transplantation antigen, was compared by flow microfluorometry to the expression of products of H-2K and H-2D loci, using monoclonal antibodies. By this methodology, the ontogeny and tissue distribution of Ld antigens were found to be indistinguishable from those of the K and D antigens. In a reciprocal blocking assay, using fluorescein-labeled test reagents, it was shown that monoclonals anti-H-2.65 and anti-H-2.64 did not inhibit the binding of each other. These results suggest that the alloantigenic determinants H-2.64 and H-2.65 are located at distinct sites on Ld molecules. Quantitative comparisons using the fluorescein-labeled monoclonal reagents indicated that Ld molecules are expressed at 2- to 3-fold lower levels on the cell surface compared with K and D molecules. These findings give new credence to a "3-locus" model for the major histocompatibility complex of man and mouse, where H-2L and HLA-C share several homologies that are unique and distinguish them from the other histocompatibility loci.
mesh_terms: D000818:Animals; D000906:Antibodies; D000911:Antibodies, Monoclonal; D000918:Antibody Specificity; D001667:Binding, Competitive; D002452:Cell Count; D005455:Fluorescent Antibody Technique; D005470:Fluorometry; D006183:H-2 Antigens / Q000235:genetics / Q000276:immunology*; D008214:Lymphocytes / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL
chemical_list: D000906:Antibodies; D000911:Antibodies, Monoclonal; D006183:H-2 Antigens